1. Field of the Invention
The present invention relates to irrigation sprinklers, in general, and to an improved impact sprinkler unit, in particular.
2. Prior Art
Many regions of the world today use irrigation systems for the artificial distribution of water. One of the most widely used irrigation systems, particularly where water is not abundant or plentiful, is the sprinkler system wherein one or more sprinkler units are positioned about a land area for distributing water over the surface of the land area. Such systems are widely used in most developed countries for lawns, golf courses, playing fields and many field crops.
Impact sprinklers, in general, are well known in the art. Such sprinklers have been used for many years. Impact sprinklers are, generally, of two broad varieties or types. The first type is the open or common riser mounted sprinkler which is merely attached to the end of a riser stem or pipe formed by a water conduit. The second type is a similar sprinkler unit which is mounted within a housing which is, in turn, frequently buried beneath the surface of the ground so that the sprinkler is a "pop-up" unit.
The first type of sprinkler is most often used in open areas such as flower beds or the like which do not require close trimming, for example by a lawnmower of the like. These units extend upwardly from the surface and are somewhat obtrusive and unattractive. Consequently, they are used in areas where they are not readily observed.
The second type of sprinkler is most often used in lawn settings and is mounted within housings (or wells) which are buried underground. The top of the housing is substantially flush with the surface which can be easily mowed. The sprinklers, per se, are arranged to "pop-up" (or rise above the housing and the ground surface) when water is supplied. In this fashion, the sprinklers remain out of sight until activated.
However, the housings for this type of sprinkler, being open by design to accomodate the standard impact sprinkler arm, tend to become filled with debris such as dirt, grass clippings and the like. Any of the above hamper the ability of the sprinkler to pop-up, to retrace and the arm's ability to drive the sprinkler.
Also, known in the art are gear driven sprinklers wherein the nozzle is, effectively, rotated by a gear driving mechanism which is activated by the water applied to the sprinkler. These sprinklers have the advantage that their housings are closed by nature avoiding the open or well design of an impact sprinkler. However, it has been determined that these sprinklers are frequently subject to failure due to debris becoming engaged in the gear drive mechanism. As a consequence, a new design of sprinklers is needed.